521285 has 8 divisors (see below), whose sum is σ = 630936. Its totient is φ = 413440.

The previous prime is 521281. The next prime is 521299. The reversal of 521285 is 582125.

It is a Cunningham number, because it is equal to 722²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 1 + 521284 = 1^2 + 722^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 521285 - 2² = 521281 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 521285.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 305 + ... + 1065.

It is an arithmetic number, because the mean of its divisors is an integer number (78867).

2⁵²¹²⁸⁵ is an apocalyptic number.

It is an amenable number.

521285 is a deficient number, since it is larger than the sum of its proper divisors (109651).

521285 is a wasteful number, since it uses less digits than its factorization.

521285 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 903.

The product of its digits is 800, while the sum is 23.

The square root of 521285 is about 722.0006925204. Note that the first 3 decimals coincide. The cubic root of 521285 is about 80.4806995639.

The spelling of 521285 in words is "five hundred twenty-one thousand, two hundred eighty-five".